Injection pump

ABSTRACT

An injection pump including an inlet valve, an outlet valve, a pump chamber communicating with the volume between the inlet and outlet valves, a piston movable in the chamber, means for driving the piston between a zero displacement volume position and a maximum displacement volume position, and means for adjusting the maximum displacement volume of the piston.

United States Patent Marten [4 1 Jan. 18, 1972 [54] INJECTION PUMP 2,205,828 6/1940 Brown ..417/435 2,291,889 8/1942 Evans et al.... ...92/13.8 [72] Inventor. Donald J. Marten, Plymouth, Mass. 2,596,943 5/1952 Sheen 092/118 [73) Assignee: W. C. Bonner Company, Inc., Watertown, 2,651,995 9/ 1953 Blackburn ....417/44 Mass. 2,907,614 10/1959 Rosen ...92/13.8 2,980,024 4/1961 Pope ...92/13.8

9 [22} PM 4 1 69 3,150,570 9/1964 Johnson. ....92/243 [21] Appl.No.: 855,322 3,286,933 11/1966 Savage ..417/568 52 u.s.c| ..417/568, 92/13.51,92/13.8 Primary 51 m. an ..F04b2l/02,F04b49/00 s-landwm [58] Field ofSearch ..92/l3.8,13.4, 13.51, 205,

92 206, 243; 417/568, 454, 435 1571 ABSTRACT [56] References Cited An injetlitionbpump including an inlgl Lalve, an outlet valve, a pump c am er communicating wit t e volume between the UNXTED STATES PATENTS inlet and outlet valves, a piston movable in the chamber, means for driving the piston between a zero displacement McClure volume positign and a maximum displacement volume posi 721,64 2/ 1 Westermafl 417/563 tion, and means for adjusting the maximum displacement 1,571,845 2/1926 Lefebvte.... ..417/568 volume fth piston, 1,770,683 7/1930 Davis ..417/454 3/1940 Oniows ..92/206 4 Claims, 4 Drawing Figures PRESSURE SWITCH PATENIEU m1 8 m2 INVENTOR.

N m M M J m m 0 0 ATTORA/EX INJECTION IIUMP BACKGROUND OF INVENTION This invention relates to injection pumps, and more particularly to such pumps for introducing small, precise quantities of a first fluid into a second fluid.

A number of conventional pumps used to introduce small, precise amounts of fluid into another fluid, such as the pumps used to inject wetting agents in the rinse water of dishwashing machines in commercial establishments, suffer from high initial cost and high maintenance costs. Further, they are difficult to service, necessitating in most cases the attention of trained personnel to repair them. This is a definite disadvantage when a breakdown occurs during peak restaurant hours and glassware cleaned but carrying water stains must be presented to diners. Often such pumps have difficulty in starting because of air trapped in the pump and they are not easily adjustable whereby kitchen employees or even trained service personnel can easily set them for precisely the amount of fluid to be injected.

SUMMARY OF INVENTION It is therefore an object of this invention to provide an inexpensive, reliable, low'maintenance, long-life injection pump which is self-bleeding and self-priming, has an adjustable pumping volume and has simply and easily replaceable basic parts.

It is a further object of this invention to provide an injection pump having a zero displacement volume position and a maximum displacement volume position which maximum displacement volume position is adjustable for varying the volume of fluid pumped during each stroke of the pump.

It is a further object of this invention to provide an injection pump which minimizes the volume in which air may be trapped and provides for easy unassisted escape of such trapped air.

It is a further object of this invention to provide an injection pump which includes a bleeder valve for removing excess air from the pump without the use of tools.

It is a further object of this invention to provide an injection pump in which both the pump and drive motor are individually andjointly removable and replaceable and are flexibly mounted relative to each other to prevent jamming of the drive motor should pump action become restricted.

The invention features an injection pump including an inlet valve for permitting introduction of fluid to the pump during an intake cycle and preventing back flow of fluid during a pumping cycle. An outlet valve permits fluid to pass from the pump during a pumping cycle and prevents return to the pump of passed fluid during an intake cycle. There is a pump chamber communicating with the volume between the inlet and outlet valves and a piston movable in that chamber. Drive means move the piston between a zero displacement volume position and maximum displacement volume position and there are means for adjusting the maximum displacement volume position of the piston.

DISCLOSURE OF PREFERRED EMBODIMENT Other objects, features and advantages will occur from the following description of a preferred embodiment and the accom'panying drawings, in which:

FIG. I is an elevational view of an injection pump according to this invention.

FIG. 2 is an enlarged axonometric view of the drive shaft and drive wheel that moves the pump piston.

FIG. 3 is an axonometrie view of the pump and drive motor supported in operating relationship by their mountings.

FIG. 4 is a partially broken away view of the pump of FIG. 3 showing the mounting of the drive motor.

There is shown in FIG. I an injection pump having a chamber 12 in which piston 14 is slidably driven by wheel 16 rotatable on pin 17 driven eccentrically about axis 18 of shaft 20 driven by motor 22, FIG. 2. Wheel 16 pushes on forward bearing surface 24 of recess 26, FIG. 3, in enlarged section 26 of piston 14 to move piston I4 to its zero displacement volume position against wall 30, as shown in FIG. I, and pushes on rearward bearing surface 32 of adjusting screw 34 in recess 26 in enlarged section 28 of piston 14 to move piston 14 to its maximum displacement volume position. Threads 36 on screw 34 engage threads 38 in bore 40 in section 28 enabling a gradual, uniform adjustment of the retraction of piston 14 without effecting the zero displacement volume position of piston 14. Screw 34 may have a knurled edge 42 for finger adjustment or a slot 44 for receiving a screwdriver. There are 0- rings 46, 50 in grooves 52, 56 to seal piston I4 against chamber 12, and a third groove 54 which supplies additional oil-retention capacity.

Chamber I2 is charged during the intake stroke and discharged during the pumping stroke of piston 14 by the fluid in compartment 58 formed by sleeve 60 within pipe 62 between ball valves 64, 66 and communicating with chamber 112 through bore 68 in sleeve 60 and bore 70 in wall 30. A connection block 72 may be provided to facilitate joining of chamber I2 and pipe 62 such as by welding or brazing. On the intake stroke of piston 14 ball 64 is drawn tightly against its seat, O-ring 74, and ball 66 is drawn away from its seat, O-ring 76, permitting entry of fluid from input line 78. Input line 78 may be connected to a reservoir of fluid 80 to be pumped such as inverted bottle 82, a tank 84 beneath the pump or a further input line from a remote source. This pump is capable of drawing its charge from all such reserves whether close or distant, or higher or lower than the pump. Line 78 is conventionally coupled with pipe 62 and sleeve 86 therein by means ofa nut 88 with compressible washers not shown.

Output line 90 may be coupled to pipe 62 and sleeve 92 therein through a bleeder valve 94 that couples to pipe 62 and sleeve 92 by means of nut 96 similar to nut 88 and to line 90 by means of a similar nut 98. Since no air can be trapped in chamber I2 because piston 14 fully closes upon wall 30 at the end of each discharge stroke, air in the system is left in compartment 58 from whence it naturally rises through ball valve 64 to the upper portion of bleeder valve '94 from whence it can be permitted to escape through hole I00, FIG. 3, by turning wheel I02.

MOtor 22 may be connected to a power source manually when pumping action is desired or automatically by means of a pressure switch 104 in the rinse water line of a dishwashing machine, for example, that closes when the pressure in the rinse line exceeds a predetermined level, or automatically by connection with the electrically energized rinse valve 106 so that both are energized simultaneously. Motor 22 may be contained in a housing I08, FIG. 4, fastened to mounting plate 110 by screws I12. Plate 110 may be fastened to mounting plate 114 which supports pump 10 by screws I16 passing through housing 108. Motor 22 may be arranged to drive an internal gear, not shown, that drives gear I18, FIGS. 3 and 4, and which in turn drives gear I20 movable with shaft 20. Chamber I2 is snugly fitted in bore I22 of plate I14 and secured by adjusting screw 124 in the proper position relative to drive wheel I6 to insure that piston I4 meets wall 30 upon completion of each discharge stroke. Plate 114 may be fastened to a base I26 by screws I28 and either or both plates 110 and 114 may be sufficiently flexible to permit them to flex thereby enabling wheel I6 to continue motion and prevent jamming or overloading the motor should the pump motion become restricted. In FIG. 3 the necessary flexure is contributed by mounting plate 110.

A failure of the drive system may be serviced by removing screws 116 and replacing the assembly including plate 110 and housing 108 with motor 22, gears IIS, 120, shaft 20 and wheel I6 with a new assembly 130 without destroying the setting of the pumping volume. Similarly, a failure in the pumping mechanism is repaired by removing screws I16, screws 128, and uncoupling lines 78 and 90 at 88 and 98 replacing assembly 132 including mounting plate I14, pipe 62, chamber 12 and piston I4 with a new assembly, then refastening assembly 130 to the new assembly [32 without destroying the setting of the pumping volume. The maximum pumping volume may be varied by turning screw 34 and air in the system may be removed by manipulating wheel 102.

The pump may be used in various environments and in vari ous positions. If the compartment 58 is inclined to the vertical, springs 134 or other biasing means may be required to assist or replace gravity as a means for positively controlling balls 64,

Other embodiments will occur to those skilled in the art and are within the following claims:

What is claimed is:

1. An injection pump comprising an inlet valve for permitting introduction of fluid to the pump during an intake stroke and preventing backflow of fluid during a discharge stroke; an outlet vertically spaced from the inlet valve for permitting discharge of fluid from the pump during a discharge stroke and preventing return to the pump of discharged fluid during the intake stroke; a first chamber located between the spaced said inlet and outlet valves; a pump chamber adjacent and communicating with said first chamber; a piston movable in said pump chamber between a zero displacement position in which said piston is closest to said first chamber and a maximum displacement position in which said piston is most distant from said first chamber; means for driving said piston forward to said zero displacement position on the discharge stroke and rearward to the maximum displacement position on the intake stroke; said piston including a first means for engaging said means for driving for moving said piston forward towards the zero displacement position during the discharge stroke and second means for engaging said means for driving for moving said piston rearward towards the maximum displacement position during the intake stroke; means for adjusting the position of said second means for engaging relative to said first means for engaging and said means for driving for varying the location of the maximum displacement position and stroke of said position and, first mounting means for supporting said first chamber and second mounting means for supporting said means for driving, at least one of said first and second mounting means being flexible to enable distorting of the relationship between said means for driving and said first and second means for engaging to prevent jamming therebetween when motion of said piston is restricted.

2. The pump of claim 1 in which said means for driving includes a drive shaft and an eccentric member mounted on said drive shaft.

3. The pump of claim 2 in which said first means for engaging includes a first surface transverse to the direction of travel of said piston and said second means for engaging includes a second surface transverse to the direction of travel of said piston 4. The pump of claim 3 in which said means for adjusting includes a threaded member carrying said second surface and threadably engaged with said piston for movement in a direction transverse to said second surface. 

1. An injection pump comprising an inlet valve for permitting introduction of fluid to the pump during an intake stroke and preventing backflow of fluid during a discharge stroke; an outlet vertically spaced from the inlet valve for permitting discharge of fluid from the pump during a discharge stroke and preventing return to the pump of discharged fluid during the intake stroke; a first chamber located between the spaced said inlet and outlet valves; a pump chamber adjacent and communicating with said first chamber; a piston movable in said pump chamber between a zero displacement position in which said piston is closest to said first chamber and a maximum displacement position in which said piston is most distant from said first chamber; means for driving said piston forward to said zero displacement position on the discharge stroke and rearward to the maximum displacement position on the intake stroke; said piston including a first means for engaging said means for driving for moving said piston forward towards the zero displacement position during the discharge stroke and second means for engaging said means for driving for moving said piston rearward towards the maximum displacement position during the intake stroke; means for adjusting the position of said second means for engaging relative to said first means for engaging and said means for driving for varying the location of the maximum displacement position and stroke of said position and, first mounting means for supporting said first chamber and second mounting means for supporting said means for driving, at least one of said first and second mounting means being flexible to enable distorting of the relationship between said means for driving and said first and second means for engaging to prevent jamming therebetween when motion of said piston is restricted.
 2. The pump of claim 1 in which said means for driving includes a drive shaft and an eccentric member mounted on said drive shaft.
 3. The pump of claim 2 in which said first means for engaging includes a first surface transverse to the direction of travel of said piston and said second means for engaging includes a second surface transverse to the directiOn of travel of said piston.
 4. The pump of claim 3 in which said means for adjusting includes a threaded member carrying said second surface and threadably engaged with said piston for movement in a direction transverse to said second surface. 